1. Field of the Invention
This invention relates to a liquid accumulator for minimizing pressure surges associated with the operation of a reciprocating pump. The accumulator is especially useful in engine fuel supply systems that employ reciprocating fuel pumps for developing fuel supply pressure.
2. Description of Prior Developments
Accumulators have been used in engine fuel supply systems to minimize or dampen fuel pressure surges associated with the operation of pistonoperated fuel pumps. The following U.S. Patents show engine fuel supply systems having accumulators for minimizing pressure surges:
U.S. Pat. No. 3,412,718 to Long granted Nov. 26, 1968 PA0 U.S. Pat. No. 4,161,161 to Bastenhos granted Jul. 17, 1979 PA0 U.S. Pat. No. 4,440,134 to Nakao et al. granted Apr. 3, 1984 PA0 U.S. Pat. No. 4,462,368 to Funada granted Jul. 31, 1984 PA0 U.S. Pat. No. 4,615,320 to Fehrenback granted Oct. 7, 1986.
In some cases, even with the presence of an accumulator in the fuel system, premature failure of the pump seals can occur due to seal damage caused by pressure spikes. The presence of such pressure spikes or surges may be due to the fact that the accumulator is often located a considerable distance downstream from the pump. The seal failure problem is aggravated when there is no check valve between the pump and the accumulator.
When the accumulator is located remote from the pump, a relatively large mass of high energy liquid accumulates between the accumulator and the pump outlet port. As the accumulator accepts the surging liquid at the beginning of each pump output stroke, a back-flowing pressure surge is generated and propagated back toward the pump due to the inertia of the large liquid mass located between the accumulator and pump. The resulting pressure surge developed in overcoming this inertia exerts a peak force on the pump seals which may lead to premature seal and pump failure.